\[\boxed{\mathbf{913}.\ }\]
\[1)\ 10\ :6 = \frac{10}{6} = \frac{6 + 4}{6} = 1\frac{4}{6}\]
\[2)\ 18\ :5 = \frac{18}{5} = \frac{15 + 3}{5} = 3\frac{3}{5}\]
\[3)\ 23\ :11 = \frac{23}{11} = \frac{22 + 1}{11} = 2\frac{1}{11}\]
\[4)\ 19\ :6 = \frac{19}{6} = \frac{18 + 1}{6} = 3\frac{1}{6}\]
\[5)\ 55\ :6 = \frac{55}{6} = \frac{54 + 1}{6} = 9\frac{1}{6}\]